The present invention relates to improvements in or relating to the ink supply device for use in portable labeling machines of the type disclosed, for example, in U.S. Pat. No. Re. 27,889. More specifically, the invention deals with a device utilizing cartridges for supplying ink to the printing mechanism of a labeling machine.
The printing mechanism of the labeling machine under consideration is used for printing inscriptions on each of a series of labels fed by indexed movement along a travel path thereof within the machine. Upon manual actuation of the machine, the printing types of the printing mechanism is brought in the position faced on successive blank labels and pressed onto each of said labels. The printing types is customarily inked by a roller which is made of spongy material impregnated with ink and which is usually spring-actuated into circumferential contact with the drum.
Upon exhaustion of the ink impregnated in the inking roller, a suitable squirt has heretofore been employed to manually re-impregnate the roller in situ with a fresh supply of ink. In this manner, however, the ink tends to premeate unevenly through the roller, with the result that the printed characters on the labels are of inconsistent ink density and are sometimes undecipherable. Moreover, the ink squirted inadvertently or in an excess amount is liable to smear the machine, the articles to be labeled, and the operator's hands and clothes.
In another known method, the exhausted inking roller is replaced by a new, identical roller. The ink supply device constructed according to this method requires the direct handling of the rollers for their replacement, so that the operator's hands and clothes are also likely to be smeared. Other additional difficulties involved in the prior ink supply devices are that the inking roller cannot be readily and securely mounted on and dismounted from the roller holder and that the inking roller holder itself cannot be readily and securely attached to or detached from the labeling machine.
It has also been proposed to replace the exhausted inking roller together with its holder by a new roller combined with its own holder. This scheme is not sufficiently practical in view of the high expenses involved.
The labeling machine in question is perhaps best adapted for affixation of price tags to merchandise in stores, supermarkets and like commercial estabilshments. As will be surmised from the above noted state of the art, one often finds tags that are illegible, due obviously to the improper supply of ink to the printing mechanism of the machine. Recently, in large supermarkets and the like, there is a growing trend to employ automatic optical readers to sense the data printed on the price tags. This is all the more reason why the tags are required to bear even more clear-cut inscriptions than heretofore.